(a) Field of the Invention
The present invention relates to a device for gain control and a method for receiving a signal.
(b) Description of the Related Art
In general, a receiving apparatus of a wireless communication system amplifies a received wireless signal with a predetermined gain. In this operation, when the gain is set so large that it departs from the operational range of an analog-to-digital converter (A/D converter), the signal is distorted in the digital region, or when the gain is set too small, quantization noise increases and demodulation performance is deteriorated. Therefore, automatic gain control, which maintains an output signal at a predetermined level even if an input signal changes, is required. The automatic gain control controls a gain, for example, by deriving a control signal on the basis of the power of a preamble.
On the other hand, a beam that is a wireless signal with directionality of a wireless communication system may be formed to radiate an electric wave only in a predetermined desired direction in an antenna. However, a beamforming symbol and a non-beamforming symbol simultaneously exist in one frame, and a power difference is generated between the beamforming symbol and the non-beamforming symbol according to the beamforming performance and channel environment. Controlling a gain on the basis of only the power of the preamble does not consider the power of the beamforming symbol, such that it is difficult to perform accurate gain control. Therefore, specific gain control considering the power of the beamforming symbol is required when a beamforming symbol and a non-beamforming symbol simultaneously exist.
Further, a multiple input multiple output (MIMO) antenna has been recently used in wireless communication systems for high speed communication, in which specific gain control for a wireless signal received by the MIMO antenna is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.